Work vehicles with endless elastomeric track belts have been successfully employed to perform various types of tasks in construction, earth-moving, and agricultural endeavors. As with metal chain type track assemblies, the endless elastomeric track belt equipped work vehicle typically includes a carriage assembly having at least one drive wheel and a plurality of roller wheels functioning as idler wheels for supporting and distributing the weight of the vehicle along the length of the track in ground contact. These roller assemblies typically include a relatively larger idler wheel at the end of the endless track loop opposite the drive wheel.
Work vehicles having such elastomeric endless track belts have been discovered to provide numerous advantages as compared to conventional metal track type work vehicles or wheel type work vehicles. For example, a work vehicle having such elastomeric track belts can be safely operated on conventional paved or asphalted road surfaces without causing damage thereto, thereby rendering unnecessary the need for disconnecting equipment and providing separate transport for both the work vehicle and its associated equipment when crossing or being transported on such roadways. Another advantage of such vehicles is reduced soil compaction and improved tractive effort per pound of vehicle weight as compared to conventional wheel type vehicles, which is especially beneficial when the work vehicle is employed in an agricultural endeavor. Also, such work vehicles offer additional advantages in terms of reduced weight and reduced costs of maintenance, especially as compared to conventional metal track type vehicles. One problem typically encountered in the use of the elastomeric track belt is the increased difficulty in assuring that the track belt remains properly centered on the drive wheel, roller wheel sub-assemblies, and idler wheel. The typical metal track type link can readily be provided with inwardly directed lugs which are relatively inflexible and generally satisfactorily assure that the track link will be suitably guided along the endless loop. However, the elastomeric track belt is substantially more flexible, and care must be taken in the design of such vehicles to compensate for this flexibility and assure that the elastomeric track belt will properly follow the designated loop path.
One earlier attempt to assure that the elastomeric track belt will properly follow the loop path is disclosed in U.S. Pat. No. 5,368,115, issued to Elmer R. Crabb on Nov. 29, 1994. This patent discloses a work vehicle having elastomeric track belts which operate on self-aligning roller idler wheels, to insure that the roller idlers disposed between the drive wheel and the idler wheel will remain aligned properly with the ground contacting portion of the elastomeric drive belt. The patent also discloses a self-contained tensioning means for insuring that the operating tension of the elastomeric track belt would be properly maintained during the operation of the work vehicle. Such a tensioning means permits the elastomeric track belt to have a degree of flexibility by permitting an increase or decrease in the length of the loop path and the ground contact portion during the operation of the work vehicle, thus decreasing the chance of a single point contact between the elastomeric track belt and the ground when operating on rough surfaces. However, it is also well known that during the operation of track equipped work vehicles, a substantial amount of lateral force may be exerted on the track belt during turning and other maneuvers as well as during sidehill operations. Just as misalignment with the roller idlers tends to cause excessive heat and wear of the elastomeric track belt, misalignment with the idler wheel also causes excessive heating and wearing of the track belt. This excessive heat and wear can cause premature failure of the elastomeric track belt, thus increasing the expense of maintenance and operation of a work vehicle so equipped.
Therefore, it is an object of the present invention to provide a means for insuring proper alignment of the elastomeric track belt with the idler wheel.
It is another object of the present invention to provide such an idler wheel self-alignment means as will be easily adapted to work vehicles.
It is yet another object of the present invention to provide such an idler wheel self-alignment means as will be relatively inexpensive to manufacture.
It is yet a further object of the present invention to provide such an idler wheel self-alignment means as will be relatively inexpensive to manufacture and to maintain.
It is yet a further object of the present invention to provide such an idler wheel self-alignment means as will cause reduced heating and wear of an elastomeric track belt when employed therewith.
It is another object of the present invention to provide such an idler wheel self-alignment means as will be responsive to lateral forces exerted upon the elastomeric track belt.